Azo dye.



UNITED STATES PATENT UFFIGE.

OSCAR DRESSEL AND MYRTIL KAHN, OF ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN VO'RM. FRIEDR. BAYER & CO, OF ELBERFELD, GERMANY, A QORPORATION OF GERMANY.

AZO DYE.

Specification of Letters Patent.

Patented. Feb. 5, 1907.

To all whom it may concern:

Be it known that we, OSCAR DRESSEL and MYRTIL KAHN, citizens of the German Enipire, Kingdom of Prussia, residing at Elberfeld, Germany, have invented new and useful Improvements in new Azo Dyes, of which the following is a specification.

This invention relates to the manufacture and production of new azo dyestuffs prepared from the hitherto unknown 5-nitro-4- chloro-2-aminophenol and sulfonic acids of naphtholic compounds, such as sulfonic acids ofnaphthols, dioxynaphthalenes,aminonaphplipls or their substitution derivatives, or the The 5nitro4-chloro-2-aminophenol is obtained by treating with nitratin agents the ethenyl derivative of the 4-cliloro-2-aminophenol. (See American Chemical J oarnal, Vol. 32, page 42.) The nitro-ethenyl compound thus obtained (M. P. 148 149 centigrade) yields on boiling with dilute mineral acids the 5-nitro-4-chloro2aminophenol. It can be also obtained by treating the 4-chloro-2-aminophenol itself with nitrating agents. In this case, however, its isome tlie known 6-nitro-4-chloro2a1ninophenol is formed simultaneously with the 5-nitro-4-chloro-2-aminophenol.

The 5-nitro-4-ehloro-2-aminophenol forms yellow needles soluble in alcohol. On being eated over 200 they grow darker and melt at about 225 centigrade with evolution of as. g The new dyestuffs are in the sha e of their alkaline salts dark powders solu le in water, yielding upon reduction with stannous chlorid and hydrochloric acid 2-5-diaminoi-chlorophenol and sulfonic acids of aminonaphtholic compounds, dyeing wool from acid-baths generally from red to violet shades which are changed to green to blue to black when chromed after dyeing.

In carrying out the new process practically the following examples are given, the parts being by weight.

Exam le 1: A mixture of six parts of nitric acid (40 Baum) and nine parts of sulfuric acid monohydrate are slowly stirred into a solution of ten parts of ethenyl-4-chloro-2- aminophenol V (Oily-l N 06H; Cl(

in thirty parts of sulfuric-acid monohydrate. To complete the reaction, the temperature is allowed to rise to 30 to 40 centigrade for a short, time. The mixture of the reaction is then poured into ice-water, when .the nitro product will be separated. For saponification' of the nitro compound it is boiled with twelve times its quantity of a twenty-percent. sulfuric acid until all is entered into solution. 1101 is then precipitated from the mass 0 the reaction by the addition of sodium carbonate or sodium acetate. It is filtered off and dried. On nitrating the -i-chloro-2-aminophenol a mixture of two isomeric nitro compounds is obtained. The 5-nitro-4-chloro- Z-aminophenol can be separated from the 6-nitro4-chloro-2-amino henol. by a fractional crystallization id om alcohol. The 6-nitro-4-chloro-2-aminophenol deposits first, and the 5-nitro-4-chlore-fZ-aminophenol can be isolated from the alcoholic solution. 18.9 parts of diazotized in the usual manner by means of hydrochloric acid and seven parts of sodium nitrite. The diazo com ound, which is partly precipitated in the s red crystals, is then poured into a solution of 24.6 partsof the sodium salt of l-naphthol- 4-sulfonic acid, to which suflicient sodium carbonate has been added to maintain the reaction strongly alkaline throughout the whole process. After some hours the dyestuif, which has separated out almost entirely, is completely precipitated by the ad dition of common salt, filtered ofi and dried. It dyes wool from acid-baths red shades which on chroming change to a dark navy blue.

aminophenol are diazotizedin the usual way and then combined with thirty-two parts of 2-phenylamino- 5 naphthol-7 -sulfonic acid dissolved in an excess of a sodium-carbonate 5-nitroi-chloro-2-aminophenol are- The 5nitro-4-chloro2amino he Example 2 i 18.9 parts of nitro-4-chloro2.

8o ape of yellowishsolution. The dyestuif separates completely after a short time. It is in the sha e of its sodium salt after being dried and pu verized a dark powder soluble in water with a violet rcolor; soluble in concentrated sulfuric acid dyes.

Dyes wool when Dyestufi' from the diazo com ound of 5-nitro-4 cliloro2-amincp enol. chromed dyeing.

l. 1-napl1thol-4-sulionic acid Reddish blue. 2. l-napl1thol5-sulfonic acid. Greomsh blue. 3. l-naphtliol-3.Gdisulionic a Dark blue. 4. 2-naplithoHi-sulfonic acid. Reddish blue. 5. 2-naphtl1ol-7-sulfonic acid. Black. 6. 2napl1tliol-iddisulfonic acid" Ileddisll blue. 7. l.8-aminonaphtlioI4-sulfonic acid Green. 8. l.X-aminonaphtliol-3.(l-disulfouie acid Green. 9. 2-amino-S-naplitliol7-sulfcnic acid Blue. 10. Z-pliQnylaminoaB'nnplitliol-i-sulionic acid Blue. 11. 2-axnino-8 naphtliolu-sulionic acid lleddish blue. 12. l 8-di0xynaphtlmlene i-sulionic acid Greeulsh blue. 13. 1.(i-(liOXynapl1Lllaleiiefl-mllfoflic acid Dark blue. 14. 1.8-dioxyuaphtli'alcnodl.6-disulfonic acid Greenisli blue.

Having now described our invention and in what manner the same is to be performed, what we claim is 1. The herein-described new azo dyestufis obtainable by combining the diazo compound of 5-nitro-4-chloro-2-aminophenol with sulfonic acids of naphtholic compounds, WhlCh dyestufls are, after being dried and pulverized, in the shape of their alkaline salts dark powders soluble in water; yielding upon reduction with stannous chlorid and hydrochloric acid 2-5-diaminoi-chlorophenol and sulfonic acids of aminonaphtholic C0111- pounds; and dyeing wool from acid -baths generally from red to violet shades, which on chroming change to from green to blue to black, substantially as hereinbefore described.

2. The herein-deshribed new azo dyestufl' obtainable 3y combining the diazo comp'ound of 5-nitro-4-chloro-2-aminophenol with 2- phenylamino 5 naphthol 7 sulfonic acid, which dyestuff is, after being dried and pulverized, in the shape of its sodium salt a dark powder soluble in water with a violet color and in concentrated sulfuric acid with a bluish-red color; yielding upon reduction with stannous chlorid and hydrochloric acid 25-diamino-4- chlorophenol and Q-phenylamino-5-naphthol- .6-amino-7-sulf0nic acid; and dyeing wool from acid-baths bordeaux shades which are changed to blue when chromed after dyeing, substantially as hereinbefore described.

In testimony. whereof We have hereunto set our hands in the presence of two subscribing witnesses.

OSCAR DRESSEL. MYRTIL KAI-IN.

\Vitnesses:

Q'rro KoNIG, J. A. RITTERSHAUS. 

